Nanocrystalline ceramic structures have a grain size of 100 nanometers (“nm”) or less. They can exhibit superior properties over their coarser polycrystalline (i.e. many grained) counterparts, and are attractive for many different areas including optical, microelectronic, magnetic, structural, thermal, electric, chemical, and refractory applications.
Nanocrystalline ceramic structures may be formed by sintering ceramic nanopowder (i.e. powder with particle sizes of about 100 nm or less), which typically involves heating ceramic powder or a green body made from ceramic powder to a temperature below the melting point, sometimes under pressure. The final sintered structure is polycrystalline.
All conventional sintering methods cause some grain growth that can result in grains much larger than those of the starting nanopowder.